scholarly journals Inhibition of BCL11B induces downregulation of PTK7 and results in growth retardation and apoptosis in T-cell acute lymphoblastic leukemia

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kehan Li ◽  
Cunte Chen ◽  
Rili Gao ◽  
Xibao Yu ◽  
Youxue Huang ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Growth Retardation ◽  
Lymphoblastic Leukemia ◽  
Downstream Target ◽  
B Cell Leukemia ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Induced Apoptosis ◽  
Necrosis Factor ◽  
Aggressive Subtype

AbstractT-cell acute lymphoblastic leukemia (T-ALL) is an aggressive subtype of leukemia with poor prognosis, and biomarkers and novel therapeutic targets are urgently needed for this disease. Our previous studies have found that inhibition of the B-cell leukemia/lymphoma 11B (BCL11B) gene could significantly promote the apoptosis and growth retardation of T-ALL cells, but the molecular mechanism underlying this effect remains unclear. This study intends to investigate genes downstream of BCL11B and further explore its function in T-ALL cells. We found that PTK7 was a potential downstream target of BCL11B in T-ALL. Compared with the healthy individuals (HIs), PTK7 was overexpressed in T-ALL cells, and BCL11B expression was positively correlated with PTK7 expression. Importantly, BCL11B knockdown reduced PTK7 expression in T-ALL cells. Similar to the effects of BCL11B silencing, downregulation of PTK7 inhibited cell proliferation and induced apoptosis in Molt-4 cells via up-regulating the expression of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and p27. Altogether, our studies suggest that PTK7 is a potential downstream target of BCL11B, and downregulation of PTK7 expression via inhibition of the BCL11B pathway induces growth retardation and apoptosis in T-ALL cells.

Activation of the JNK Pathway Mediates Chemoresistance in T-Cell Acute Lymphoblastic Leukemia by Phosphorylation and Proteosomal Degradation of BimEL.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2372-2372
Author(s):  
Kam Tong Leung ◽  
Karen Kwai Har Li ◽  
Samuel Sai Ming Sun ◽  
Paul Kay Sheung Chan ◽  
Yum Shing Wong ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Cytochrome C ◽  
Cell Lines ◽  
Caspase 3 ◽  
Lymphoblastic Leukemia ◽  
Chemotherapeutic Agents ◽  
Jnk Pathway ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Induced Apoptosis

Abstract Despite progress in the development of effective treatments against T-cell acute lymphoblastic leukemia (T-ALL), about 20% of patients still exhibit poor response to the current chemotherapeutic regimens and the cause of treatment failure in these patients remains largely unknown. In this study, we aimed at finding mechanisms that drive T-ALL cells resistant to chemotherapeutic agents. By screening etoposide sensitivity of a panel of T-ALL cell lines using DNA content and PARP cleavage as apoptosis markers, we identified an apoptosis-resistant cell line, Sup-T1. Western blot analysis and caspase activity assay showed that Sup-T1 cells were deficient in etoposide-induced activation of caspase-3 and caspase-9. In addition, mitochondrial cytochrome c release was not evident in etoposide-treated Sup-T1 cells. However, addition of exogenous cytochrome c in cell-free apoptosis reactions induced prominent caspase-3 activation, indicating that the chemoresistance observed in Sup-T1 cells was due to its insusceptibility to the drug-induced mitochondrial alterations. Analysis of the basal expression of the Bcl-2 family proteins revealed that the levels of Bcl-2 was higher in Sup-T1 cells, while Bax and BimEL levels were lower, when compared to etoposide-sensitive T-ALL cell lines. Gene silencing using antisense oligonucleotide to Bcl-2 and overexpression of Bax did not resensitize cells to etoposide-induced apoptosis. On the contrary, transient transfection of BimEL into Sup-T1 cells significantly restored etoposide sensitivity. Further experiments revealed that the lack of BimEL expression in Sup-T1 cells was due to the rapid degradation of newly-synthesized BimEL by the proteosomal pathway, as treatment of Sup-T1 cells with a proteosome inhibitor significantly restored the protein level of BimEL. Moreover, treatment with proteosome inhibitor resulted in mobility shift of BimEL, which was sensitive to phosphatase digestion. Furthermore, treatment of Sup-T1 cells with JNK inhibitor resulted in accumulation of BimEL, and pretreatment with JNK inhibitor restored sensitivity of Sup-T1 cells to etoposide-induced apoptosis, indicating that constitutive activation of the JNK pathway in Sup-T1 cells was responsible for promoting BimEL phosphorylation, and this may serve as a signal targeting BimEL to the proteosome for degradation. Altogether, our findings provide the first evidence that JNK activation correlates inversely with BimEL level by promoting its phosphorylation and degradation. This, in turn, reduces the sensitivity of T-ALL cells to chemotherapeutic agents.

scholarly journals 1,25-OH 2 vitamin D 3 and AKT-inhibition increase glucocorticoid induced apoptosis in a model of T-cell acute lymphoblastic leukemia (ALL)

2018 ◽  
Vol 9 ◽  
pp. 38-41 ◽  
Author(s):  
Maximilian Pistor ◽  
Lisa Schrewe ◽  
Steffen Haupeltshofer ◽  
Andrei Miclea ◽  
Simon Faissner ◽  
...  
Keyword(s):  
Vitamin D ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Vitamin D 3 ◽  
Induced Apoptosis

scholarly journals PRC2 loss induces chemoresistance by repressing apoptosis in T cell acute lymphoblastic leukemia

2018 ◽  
Vol 215 (12) ◽  
pp. 3094-3114 ◽  
Author(s):  
Ingrid M. Ariës ◽  
Kimberly Bodaar ◽  
Salmaan A. Karim ◽  
Triona Ni Chonghaile ◽  
Laura Hinze ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Phenotypic Variability ◽  
Chemotherapy Response ◽  
Mitochondrial Apoptosis ◽  
Loss Of Function ◽  
Apoptosis Resistance ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Induced Apoptosis

The tendency of mitochondria to undergo or resist BCL2-controlled apoptosis (so-called mitochondrial priming) is a powerful predictor of response to cytotoxic chemotherapy. Fully exploiting this finding will require unraveling the molecular genetics underlying phenotypic variability in mitochondrial priming. Here, we report that mitochondrial apoptosis resistance in T cell acute lymphoblastic leukemia (T-ALL) is mediated by inactivation of polycomb repressive complex 2 (PRC2). In T-ALL clinical specimens, loss-of-function mutations of PRC2 core components (EZH2, EED, or SUZ12) were associated with mitochondrial apoptosis resistance. In T-ALL cells, PRC2 depletion induced resistance to apoptosis induction by multiple chemotherapeutics with distinct mechanisms of action. PRC2 loss induced apoptosis resistance via transcriptional up-regulation of the LIM domain transcription factor CRIP2 and downstream up-regulation of the mitochondrial chaperone TRAP1. These findings demonstrate the importance of mitochondrial apoptotic priming as a prognostic factor in T-ALL and implicate mitochondrial chaperone function as a molecular determinant of chemotherapy response.

Inhibitory effect of hydnocarpin D on T-cell acute lymphoblastic leukemia via induction of autophagy-dependent ferroptosis

2021 ◽  
pp. 153537022110048
Author(s):  
Siyue Lou ◽  
Huanwu Hong ◽  
Liwaliding Maihesuti ◽  
Hang Gao ◽  
Zhihui Zhu ◽  
...  
Keyword(s):  
Cell Death ◽  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Lymphoblastic Leukemia ◽  
Inhibitory Effect ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Pre Treatment ◽  
Interesting Compound ◽  
Induced Apoptosis

Hydnocarpin D (HD) is a bioactive flavonolignan compound that possesses promising anti-tumor activity, although the mechanism is not fully understood. Using T cell acute lymphoblastic leukemia (T-ALL) cell lines Jurkat and Molt-4 as model system, we found that HD suppressed T-ALL proliferation in vitro, via induction of cell cycle arrest and subsequent apoptosis. Furthermore, HD increased the LC3-II levels and the formation of autophagolysosome vacuoles, both of which are markers for autophagy. The inhibition of autophagy by either knockdown of ATG5/7 or pre-treatment of 3-MA partially rescued HD-induced apoptosis, thus suggesting that autophagy enhanced the efficacy of HD. Interestingly, this cytotoxic autophagy triggered ferroptosis, as evidenced by the accumulation of lipid ROS and decrease of GSH and GPX4, while inhibition of autophagy impeded ferroptotic cell death. Our study suggests that HD triggers multiple cell death processes and is an interesting compound that should be evaluated in future preclinical studies.

scholarly journals TAL1 and LIM-Only Proteins Synergistically Induce Retinaldehyde Dehydrogenase 2 Expression in T-Cell Acute Lymphoblastic Leukemia by Acting as Cofactors for GATA3

1998 ◽  
Vol 18 (12) ◽  
pp. 6939-6950 ◽  
Author(s):  
Yuichi Ono ◽  
Norio Fukuhara ◽  
Osamu Yoshie
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Lymphoblastic Leukemia ◽  
Downstream Target ◽  
Cell Acute Lymphoblastic Leukemia ◽  
Retinaldehyde Dehydrogenase

ABSTRACT Previously, we have shown that TAL1 and the LIM-only protein gene (LMO) are regularly coactivated in T-cell acute lymphoblastic leukemia (T-ALL). This observation is likely to relate to the findings that TAL1 and LMO are highly synergistic in T-cell tumorigenesis in double-transgenic mice. To understand the molecular mechanisms of functional synergy between TAL1 and LMO in tumorigenesis and transcriptional regulation, we tried to identify downstream target genes regulated by TAL1 and LMO by a subtractive PCR method. One of the isolated genes, that for retinaldehyde dehydrogenase 2 (RALDH2), was regularly expressed in most of the T-ALL cell lines that coexpressed TAL1 and LMO. Exogenously transfected TAL1 and LMO, but not either alone, inducedRALDH2 expression in a T-ALL cell line, HPB-ALL, not expressing endogeneous TAL1 or LMO. The RALDH2 transcripts in T-ALL were, however, mostly initiated within the second intron. Promoter analysis revealed that a GATA site in a cryptic promoter in the second intron was essential and sufficient for the TAL1- and LMO-dependent transcriptional activation, and GATA3 binds to this site. In addition, forced expression of GATA3 potentiated the induction ofRALDH2 by TAL1 and LMO, and these three factors formed a complex in vivo. Furthermore, a TAL1 mutant not binding to DNA also activated the transcription of RALDH2 in the presence of LMO and GATA3. Collectively, we have identified the RALDH2 gene as a first example of direct transcriptional target genes regulated by TAL1 and LMO in T-ALL. In this case, TAL1 and LMO act as cofactors for GATA3 to activate the transcription ofRALDH2.

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